Testing 3D solar models against observations

TL;DR

This paper evaluates 3D and 1D solar models through observational tests focusing on atomic oxygen line formation, confirming the realism of the 3D model and refining non-LTE line formation constraints using high-quality SST data.

Contribution

It provides empirical validation of 3D solar models against detailed observations and refines non-LTE line formation parameters for oxygen lines.

Findings

3D model predictions agree well with observations

Centre-to-limb variation constrains non-LTE effects

Empirical correction factor for hydrogen collisions derived

Abstract

We present results from a series of observational tests to 3D and 1D solar models. In particular, emphasis is given to the line formation of atomic oxygen lines, used to derive the much debated solar oxygen photospheric abundance. Using high-quality observations obtained with the Swedish Solar Telescope (SST) we study the centre-to-limb variation of the O I lines, testing the models and line formation (LTE and non-LTE). For the O I 777 nm triplet, the centre-to-limb variation sets strong constraints in the non-LTE line formation, and is used to derive an empirical correction factor (S_H) to the classical Drawin recipe for neutral hydrogen collisions. Taking advantage of the spatially-resolved character of the SST data, an additional framework for testing the 3D model and line formation is also studied. From the tests we confirm that the employed 3D model is realistic and its predictions agree very well with the observations.